COMPARISON OF STEADY-STATE OPTICAL MODULATION SPECTRA OF B2H6-DOPED AND B(CH3)(3)-DOPED A-SI(-C)-H FILMS

A series of diborane-doped hydrogenated amorphous silicon films and a series of trimethylboron-doped hydrogenated amorphous silicon-carbon a lloys have been studied by means of steady-state optical modulation sp ectroscopy (OMS) at room temperature and at a temperature of 20 K. For both materials, the differences between doped and undoped films can b e associated with the dopant states. A comparison of the spectra of fi lms with different doping gases leads to the observation that the trim ethylboron-doped samples show a strong bleaching at low temperature, c ausing a sign reversal of the ORIS signal; this effect is ascribed to the broader band tails due to the incorporation of carbon in the films .